Gastrointestinal manifestations of cystic fibrosis

Gastrointestinal, Pancreatic, and Hepatobiliary Manifestations of Cystic Fibrosis

Pulmonary disease is the primary cause of morbidity and mortality in people with cystic fibrosis (CF), but significant involvement within gastrointestinal, pancreatic, and hepatobiliary systems occurs as well. As in the airways, defects in CFTR alter epithelial surface fluid, mucus viscosity, and pH, increasing risk of stasis through the various hollow epithelial-lined structures of the gastrointestinal tract. This exerts secondary influences that are responsible for most gastrointestinal, pancreatic, and hepatobiliary manifestations of CF. Understanding these gastrointestinal morbidities of CF is essential in understanding and treating CF as a multisystem disease process and improving overall patient care.

Gastrointestinal Manifestations of Cystic Fibrosis

Gastrointestinal symptoms of cystic fibrosis are the most important non-pulmonary manifestations of this genetic illness. Pancreatic manifestations include acute and chronic pancreatitis as well as pancreas insufficiency resulting in malnutrition. Complications in the gastrointestinal lumen are diverse and include distal intestinal obstruction syndrome (DIOS), meconium ileus, intussusception, and constipation; biliary tract complications include focal biliary cirrhosis and cholangiectasis. The common pathophysiology is the inspissation of secretions in the hollow structures of the gastrointestinal tract. Improved survival of CF patients mandates that the adult gastroenterologist be aware of the presentation and treatment of pancreatic, luminal, and hepatobiliary CF complications.

The role of endoscopy and biopsy in the management of severe gastrointestinal disease in cystic fibrosis patients

There is increasing evidence to suggest the presence of chronic inflammation in the gastrointestinal (GI) tract of cystic fibrosis (CF) patients. Some CF patients continue to have very severe gastrointestinal symptoms despite conventional CF treatment. In our center, these patients are managed in a CF gastroenterology clinic, jointly with a pediatric gastroenterologist. A number have required GI endoscopy and biopsy. The aim of our study was to characterize these patients and determine whether endoscopy and biopsy changed their management. We reviewed all the patients seen in the CF gastroenterology clinic from 2004 to 2009, who had GI endoscopies performed. The GI symptoms these patients were experiencing included abdominal pain, nausea and vomiting, rectal bleeding, failure to thrive, loose stools, and constipation. Twelve patients had GI endoscopies with mucosal biopsies performed. The median [interquartile range (IQR)] age at referral to the CF gastroenterology clinic was 4 years [0.9-8]. Their body mass index (BMI) was 15.2 [13.7-15.5]. Twenty-five percent were homozygous delta F508. Two patients had previously had meconium ileus as neonates requiring surgical intervention. One other patient had needed abdominal surgery for intussusception. Ninty-two percent were pancreatic insufficient, 25% were chronically infected with Pseudomonas aeruginosa and 17% were on regularly 3 monthly intravenous antibiotics. Of the 10 patients who were able to perform spirometry, FEV1 was 101% [67-125] predicted. Nine of the 12 patients had evidence of mucosal inflammation in their biopsies, including duodenitis with eosinophilic infiltrate, chronic non-specific inactive gastritis, enteropathy with partial villous atrophy, and non-specific colitis. Immunosuppressive and anti-inflammatory therapies were commenced in these nine patients, including prednisolone, azathioprine, methotrexate, ketotifen, mesalazine, and sulfasalazine as well as the use of parenteral nutrition and elemental feeds. All the patients clinically responded to therapy. Five of the patients commenced on anti-inflammatory therapy had repeat biopsies 1-5 years following commencement of treatment and all showed histological improvement of the mucosal inflammation. GI endoscopy with mucosal biopsy has a significant role to play in the management of CF children with severe GI disease. In our study, it influenced the management in the majority of patients with severe GI symptoms. Furthermore, if GI mucosal inflammation is identified on biopsy, management with immunomodulatory agents may be clinically beneficial.

In vitro anion transport alterations and apoptosis induced by phenylbutazone in the right dorsal colon of ponies

OBJECTIVES

To study the functional and structural responses of the right dorsal colon (RDC) of ponies to phenylbutazone (PBZ) in vitro at a concentration that could be achieved in vivo.

ANIMALS

8 adult ponies.

PROCEDURE

Short circuit current and conductance were measured in mucosa from the RDC. Tissues incubated with and without HCO3- were exposed to PBZ, bumetanide, or indomethacin. Bidirectional Cl- fluxes were determined. After a baseline flux period, prostaglandin E2 (PGE2) was added to the serosal surfaces and a second flux period followed. Light and transmission electron microscopy were performed.

RESULTS

Baseline short circuit current was diminished significantly by PBZ and indomethacin, and increased significantly after addictions of PGE2. After PGE2 was added, Cl- secretion increased significantly in tissues in HCO3- -free solutions and solutions with anti-inflammatory drugs, compared with corresponding baseline measurements and with control tissues exposed to PGE2. Bumetanide did not affect baseline short circuit current and Cl- fluxes. The predominant histologic change was apoptosis of surface epithelial cells treated with PBZ and to a lesser extent in those treated with indomethacin.

CONCLUSIONS AND CLINICAL RELEVANCE

Prostaglandin-induced Cl- secretion appeared to involve a transporter that might also secrete HCO3-. Both PBZ and indomethacin altered ion transport in RDC and caused apoptosis; PBZ can damage mucosa through a mechanism that could be important in vivo. The clinically harmful effect of PBZ on equine RDC in vivo could be mediated through its effects on Cl- and HCO3- secretion.